Mass Moments: Percy Spencer, Inventor of Microwave Oven, Born Image Credit ...in 1894, Percy Spencer, the self-taught scientist who discovered the power of microwave technology, was born. With an endlessly curious mind, Spencer spent much of his early life figuring out how things worked. Orphaned as a small boy, Spencer had little schooling before he entered the workforce. But a fascination with electricity and nights of studying on his own led to a job with a new firm in Cambridge  Raytheon. During World War II, Spencer and his co-workers developed technology that gave the Allies a critical edge in radar detection. Later, a set of simple experiments based on everyday experiences resulted in the first microwave oven, the 750-pound, five-foot-tall RadarRange. Percy Spencer, a New England farm boy who never completed grammar school, grew up to be one of the world's most successful and respected electrical engineers. One colleague with a degree from M.I.T. suggested that Spencer's lack of formal education may have been an asset. "The educated scientist knows many things won't work.

Percy doesn't know what can't be done." The boy who never finished grammar school eventually earned "the respect of every physicist in the country, not only for his ingenuity, but for what he has learned about physics by absorbing it through his skin." Spencer was born in Howland, Maine. When his parents died, the boy was sent to live with an aunt who made her living as an itinerant weaver. The two traveled about New England, existing on what she earned from weaving and what he made doing any odd jobs he could find. He had to "solve [his] own situation," as he later remembered; in doing so, he learned how to get things done. Spencer's "Yankee ingenuity"  what Readers' Digest called his "itch to know"  would later help him solve engineering problems that others had either failed to notice or given up on. Spencer left school in the fifth grade to take a factory job. Four years later, the owners of a local paper mill decided to install electricity. Even though the 16-year-old Percy knew nothing about electricity, he signed on to help install the system.

He learned by trial and error and studied textbooks at night; by the time the project was finished, Percy Spencer was a skilled electrician. The new fields of electricity and wireless technology caught the young man's imagination. When he learned of the heroic role radio operators had played during the sinking of the Titanic, he joined the Navy so he could learn to be one of them. His lack of formal education meant that he had to teach himself trigonometry, calculus, chemistry, physics, and metallurgy at night. After he was discharged from the Navy at the end of WWI, the 25-year-old set off to pursue his passionate interest in electricity. About the same time, Lawrence Marshall and Vannevar Bush, who had been roommates at Tufts University in Medford, were also thinking about ways to put electricity to practical use. Thanks to Bush's position on the M.I.T. faculty, the men had good connections in the business world and in the university. They decided that electricity could be applied to labor saving devices for the household. In 1922 they founded the American Appliance Company in Cambridge; three years later, the company added Percy Spencer to its three-man staff.

In October of 1925, the company's name was changed to Raytheon ("rai" from the old French "beam of light" and "theon" from the Greek "from the gods"). In 1934 it moved from Cambridge to a former button factory in Waltham. From there, it would become one of the world's leading technology firms with employees all over the world. Its early emphasis on household appliances would evolve into a specialization in defense and space electronics. It was Percy Spencer, with his Yankee way of problem solving, who was responsible for many of the company's biggest breakthroughs. His curiosity was legendary, and he had the ability to collaborate with highly educated physicists while pursuing his characteristic "let's tinker and see" approach. One of his earliest contributions was a series of improvements to photoelectric vacuum tubes, a major step in the development of the television tube. In 1941, as the U.S. was preparing to enter WW II, he focused his efforts on the magnetron, the microwave tube in which electrons generated from a heated cathode produce radiation that could be used in radar.

Working night and day, he increased the efficiency of the magnetron and boosted output from one magnetron a week to an astonishing 2,600 a day. Radar sets Spencer designed were installed in U.S. bombers, where they were powerful enough to spot periscopes on German submarines. For this accomplishment, he won the Distinguished Public Service Award, the highest honor the Navy bestows on civilians. But Spencer is best remembered for a casual observation that would lead to a major change in food preparation. Standing next to a magnetron one day, he noticed that a candy bar in his pocket melted. This caused him to wonder if the energy from radio waves could be used to cook food. He placed popcorn kernels near the tube; within minutes, he was snacking on the world's first microwave popcorn. In 1947 Raytheon produced the first RadarRange, based on Spencer's discovery. The original microwave ovens were huge and expensive, but restaurants, vending companies, airlines, and other commercial operations realized at once the advantages of quick-cooked food. A home model went on sale in the 1950s.

The public was slow to accept the new method of cooking, but by the time Percy Spencer died in 1970, microwaves were fast becoming a nearly universal feature in American kitchens. With its world headquarters in Waltham, the company Percy Spencer helped build is now one of the largest employers in Massachusetts and a leading figure in the global defense industry. Sources The Creative Ordeal: The Story of Raytheon, by Otto J. Scott (Atheneum, 1974). "Percy Spencer and His Itch to Know," by Don Murray in Readers' Digest Magazine (August, 1958). Microwave Oven Microwave Oven Greetings, The Southwest Museum of Engineering, Communication and Computation is seeking : artifacts, books, papers, personal recollections, funny stories, newspaper clipping, magazines, catalogs, articles torn out of magazines, cartoons, prototype magnetrons, really early microwave ovens etc ANYTHING Is Fair Game! The purpose is two-fold which consists of construction the display in the museum in Glendale Arizona and also as an addition to our web site.

thanks Ed Sharpe archivist for SMECC Please check our web site at to see other engineering fields, communications and computation stuff we buy, and by all means when in Arizona drop in and see us. address: thanks Ed Sharpe archivist for SMECC The microwave oven was invented as an accidental by-product of war-time (World War 2) radar research using magnetrons (vacuum tubes that produce microwave radiation, a type of electromagnetic radiation that has a wavelength between 1 mm and 30 cm). In 1946, the engineer Dr. Percy LeBaron Spencer, who worked for the Raytheon Corporation, was working on magnetrons. One day at work, he had a candy bar in his pocket, and found that it had melted. He realized that the microwaves he was working with had caused it to melt. After experimenting, he realized that microwaves would cook foods quickly - even faster than conventional ovens that cook with heat. The Raytheon Corporation produced the first commercial microwave oven in 1954; it was called the 1161 Radarange. It was large, expensive, and had a power of 1600 watts.

The first domestic microwave oven was produced in 1967 by Amana (a division of Raytheon). In 1967, Amana, a division of Raytheon, introduced its domestic Radarange microwave oven, marking the beginning of the use of microwave ovens in home kitchens. Although sales were slow during the first few years, partially due to the ovenï¿½s relatively expensive price tag, the concept of quick microwave cooking had arrived. In succeeding years, Litton and a number of other companies joined the countertop microwave oven market. By the end of 1971, the price of countertop units began to decrease and their capabilities were expanded. Spencer, born in Howland, Maine, was orphaned at a young age. Although he never graduated from grammar school, he became Senior Vice President and a member of the Board of Directors at Raytheon, receiving 150 patents during his career. Because of his accomplishments, Spencer was awarded the Distinguished Service Medal by the U.S. Navy and has a building named after him at Raytheon. Percy Spencer, while working for the Raytheon Company, discovered a more efficient way to manufacture magnetrons.

In 1941, magnetrons were being produced at a rate of 17 per day. Spencer set out to create a simpler magnetron that could be mass produced. The result was a magnetron that replaced precision copper bars with lamina and replaced soldered internal wires with a simple solid ring. These improvements and others allowed for the faster production of 2,600 magnetrons per day. In 1945, Spencer created a device to cook food using microwave radiation. Raytheon saw the possibilities of this, and after acquiring Amana Refrigeration in 1965, was able to sell microwave ovens on a large scale. The first microwave oven was called the Radarange, and today, there are over 200 million in use throughout the world. A Brief History of the Microwave Oven By J. Carlton Gallawa , author of THE COMPLETE MICROWAVE OVEN SERVICE HANDBOOK Like many of today's great inventions, the microwave oven was a by-product of another technology. It was during a radar-related research project around 1946 that Dr. Percy Spencer, a self-taught engineer with the Raytheon Corporation, noticed something very unusual.

He was testing a new vacuum tube called a magnetron (we are searching for a picture of an actual 1946 magnetron), when he discovered that the candy bar in his pocket had melted. This intrigued Dr. Spencer, so he tried another experiment. This time he placed some popcorn kernels near the tube and, perhaps standing a little farther away, he watched with an inventive sparkle in his eye as the popcorn sputtered, cracked and popped all over his lab. The next morning, Scientist Spencer decided to put the magnetron tube near an egg. Spencer was joined by a curious colleague, and they both watched as the egg began to tremor and quake. The rapid temperature rise within the egg was causing tremendous internal pressure. Evidently the curious colleague moved in for a closer look just as the egg exploded and splattered hot yoke all over his amazed face. The face of Spencer lit up with a logical scientific conclusion: the melted candy bar, the popcorn, and now the exploding egg, were all attributable to exposure to low-density microwave energy. Thus, if an egg can be cooked that quickly, why not other foods? Experimentation began... Dr. Spencer fashioned a metal box with an opening into which he fed microwave power.

The energy entering the box was unable to escape, thereby creating a higher density electromagnetic field. When food was placed in the box and microwave energy fed in, the temperature of the food rose very rapidly. Dr. Spencer had invented what was to revolutionize cooking, and form the basis of a multimillion dollar industry, the microwave oven. (Click HERE to learn even more about Dr. Percy Spencer) Nearly 6 Feet Tall, Weighing 750 Pounds Engineers went to work on Spencer's hot new idea, developing and refining it for practical use. By late 1946, the Raytheon Company had filed a patent proposing that microwaves be used to cook food. An oven that heated food using microwave energy was then placed in a Boston restaurant for testing. At last, in 1947, the first commercial microwave oven hit the market. T hese primitive units where gigantic and enormously expensive, standing 5 1/2 feet tall, weighing over 750 pounds, and costing about $5000 each. The magnetron tube had to be water-cooled, so plumbing installations were also required.

Initial Reactions Were Unfavorable Not surprisingly, many were highly reluctant about these first units, and so they found only limited acceptance. Initial sales were disappointing...but not for long. Further improvements and refinements soon produced a more reliable and lightweight oven that was not only less expensive, but, with the development of a new air-cooled magnetron, there was no longer any need for a plumber. The microwave oven had reached a new level of acceptance, particularly with regard to certain industrial applications. By having a microwave oven available, restaurants and vending companies could now keep products refrigerator-fresh up to the point of service, then heat to order. The result? Fresher food, less waste, and money saved. New and Unusual Applications As the food industry began to recognize the potential and versatility of the microwave oven, its usefulness was put to new tests. Industries began using microwaves to dry potato chips and roast coffee beans and peanuts. Meats could be defrosted, precooked and tempered. Even the shucking of oysters was made easier by microwaves. Other industries found the diverse applications of microwave heating quite advantageous.

In time, microwaves were being used to dry cork, ceramics, paper, leather, tobacco, textiles, pencils, flowers, wet books and match heads. The microwave oven had become a necessity in the commercial market and the possibilities seemed endless. The First "Radarange" In 1947, Raytheon demonstrated the world's first microwave oven and called it a "Radarange," the winning name in an employee contest. Housed in refrigerator-sized cabinets, the first microwave ovens cost between $2,000 and $3,000. Sometime between 1952-55, Tappan introduced the first home model priced at $1295. In 1965 Raytheon acquired Amana Refrigeration. Two years later, the first countertop, domestic oven was introduced. It was a 100-volt microwave oven, which cost just under $500 and was smaller, safer and more reliable than previous models. By 1975 Sales of Microwave Ovens Exceeded that of Gas Ranges Technological advances and further developments led to a microwave oven that was polished and priced for the consumer kitchen.

However, there were many myths and fears surrounding these mysterious new electronic "radar ranges." By the seventies, more and more people were finding the benefits of microwave cooking to outweigh the possible risks, and none of them were dying of radiation poisoning, going blind, sterile, or becoming impotent (at least not from using microwave ovens). As fears faded, a swelling wave of acceptance began filtering into the kitchens of America and other countries. Myths were melting away, and doubt was turning into demand. By 1975, sales of microwave ovens would, for the first time, exceed that of gas ranges. The following year, a reported 17% of all homes in Japan were doing their cooking by microwaves, compared with 4% of the homes in the United States the same year. Before long, though, microwave ovens were adorning the kitchens in over nine million homes, or about 14%, of all the homes in the United States. In 1976, the microwave oven became a more commonly owned kitchen appliance than the dishwasher, reaching nearly 60%, or about 52 million U.S. households.

America's cooking habits were being drastically changed by the time and energy-saving convenience of the microwave oven. Once considered a luxury, the microwave oven had developed into a practical necessity for a fast-paced world. An expanding market has produced a style to suit every taste; a size, shape, and color to fit any kitchen, and a price to please almost every pocketbook. Options and features, such as the addition of convection heat, probe and sensor cooking, meet the needs of virtually every cooking, heating or drying application. Today, the magic of microwave cooking has radiated around the globe, becoming an international phenomenon. Inventor Spencer Doctor Spencer continued at Raytheon as a senior consultant until he died at the age of 76. At the time of his death, Dr. Spencer held 150 patents and was considered one of the world's leading experts in the field of microwave energy, despite his lack of a high school education. On September 18, 1999, Dr. Percy LaBaron Spencer was inducted into the National Inventors Hall of Fame and took his place in history alongside such great inventors as Thomas Edison, the Wright Brothers and George Washington Carver.

More to come on the fascinating history and development of the microwave oven... Note: Photo of Percy Spencer and Patent provided courtesy of The Spencer Family Archives Picture of the earliest microwave oven provided courtesy of The Lemelson-MIT Awards Program's Invention Dimension web site, Picture of Original Microwave Oven Patent by Doctor Percy L. Spencer Courtesy Rod Spencer and the Spencer Family Archives Copyright Information Unless otherwise noted, all materials at this cite (including without limitation all text, html markup, graphics, and graphic elements) are copyrighted ï¿½, 1989-2001 by J. Carlton Gallawa. The material available through this site may be freely used for attributed noncommercial educational purposes only. We ask that due credit and notification be given the author. Amana Radarange Amana Refrigeration, a subsidiary of Raytheon Manufacturing Company, in 1967 introduced this first compact microwave oven, called the Radarange. It was a 115 V countertop model, retailing for $495, and cooked hamburgers in 35 seconds. The compact size was made possible by a small, efficient electron tube, developed in 1964 by the Japanese, which replaced older, bulkier tubes called magnetrons.

In 1968, tests by Walter Reed Hospital confirmed many fears that microwaves did, in fact, leak out of the ovens, but Federal standards set in 1971 resolved the problem. By 1994, ninety per cent of all US homes had such an appliance. The first microwave ovens for home consumer use were introduced by Tappan in 1955, but few purchased them due to their large size (about like an electric stove) and high cost. Microwave ovens were a spin-off of wartime RADAR, and invented accidentally by Percy LeBaron Spencer of Raytheon while working on a magnetron (radar tube) near the end of the war. As he passed the device, which generated microwaves, he noticed that a candy bar in his pocket began to melt. He experimented with eggs (they exploded) and popcorn (it popped). So, a "high frequency dielectric heating apparatus" was patented in 1945 by Raytheon, and a prototype built. The first microwave oven for commercial purposes (ships and hotels) was introduced in 1947 by Raytheon, and named the Radar Range.

It stood five and a half feet tall, weighed 750 pounds, and cost $3000 30th Anniversary of Microwave Oven Marks Revolution in Americaï¿½s Home Kitchens Inventor Percy L. Spencer Biography 100 Inventions That Shaped World History by Bill Yenne, Morton, Dr. Grosser (Editor) / Paperback - 112 pages (1983) / Bluewood Books This book contains inventions from all around the world from microchips to fire. This is a really good book if you are going to do research on inventions. Accidents May Happen: 50 Inventions Discovered by Mistake by Charlotte Foltz Jones, John O'Brien (Illustrator) / Hardcover - 86 pages (1996) / Delacorte Fifty inventions discovered by mistake receive entertaining cartoon embellishment but are actually serious subjects which will delight and entertain kids. The Kid Who Invented the Popsicle: And Other Surprising Stories About Inventions by Don L.

Wulffson / Paperback - 128 pages (1999) / Puffin Brief factual stories about how various familiar things were invented, many by accident, from animal crackers to the zipper. Raytheon: A History of Global Technology Leadership Raytheons discovery of microwave cooking in 1945 was initially an accident, but its development, like so many others, can be credited to Percy Spencer. Spencer was the first, however, to discover that one could cook food using microwave radio signals. (URL: Located at Inventure Place, the online home of creative minds. Inducted Percy Lebaron Spencer in 1999 for his invention of the High Efficiency Magnetron (Patent Number 2,408,235). (URL: Celebrates inventor/innovator role models through outreach activities and annual awards to inspire a new generation of American scientists, engineers, and entrepreneurs. Featured Percy Spencer in May, 1966 for his invention of the Mictowave Oven.

(URL: web.mit.edu/invent/iow/spencer.html) In 1967, the company revolutionized the way America cooks with the introduction of the Amana Radarangeï¿½ the first countertop microwave oven for the home. (URL: Like many of today's great inventions, the microwave oven was a by-product of another technology. (URL: WORDS OF WISDOM: "He has the respect of every physicist in the country, not only for his ingenuity but for what he has learned about physics by absorbing it through his skin. He is not merely a good experimenter and a good designer; he has become, in his own right, one of the recognized individuals in a very difficult field." - Vannevar Bush DID YOU KNOW?: In 1947, Raytheon demonstrated the worlds first microwave oven and called it a "Radarange," the winning name in an employee contest. 1947 - Raytheon builds its first microwave oven. Weighing over 750 pounds and standing over five feet tall, the oven is limited to commercial use.

1967 - Using Raytheons microwave cooking technology, Amana introduces the worlds first successful 115-volt countertop microwave oven for the home. Microwave ovens are now found in over 90% of US homes The first microwave oven weighed over 750 pounds and stode over five feet tall. Housed in refrigerator-sized cabinets, the first microwave ovens cost between $2,000 and $3,000 and were sold by Raytheon primarily to the commercial marketplace. Reference Sources in BOLD Type This page revised October 20, 2006. FEATURED History of Kitchen Appliances By Mary Bellis Updated November 03, 2015. By definition, the kitchen is a room used for food preparation that is typically equipped with a stove, a sink for cleaning food and dish-washing, and cabinets and refrigerators for storing food and equipment. Kitchens have been around for centuries, however, it was not until post-civil war period that the majority of kitchen appliances were invented. The reason was that most people no longer had servants and housewives working alone in the kitchen needed culinary help.

Also the advent of electricity greatly advanced the technology of labor-saving kitchen appliances. History of Kitchen Appliances In 1850, Joel Houghton patented a wooden machine with a hand-turned wheel that splashed water on dishes, it was hardly a workable machine, but it was the first patent . Garbage Disposer Architect, inventor John W. Hammes built his wife the world's first kitchen garbage disposer in 1927. After ten years of design improvement, Hammes went into business selling his appliance to the public. His company was called the In-Sink-Erator Manufacturing Company. continue reading below our video What to Do If Your Identity is Stolen The first historical record of a stove being built refers to a stove built in 1490 in Alsace, France. Microwave Ovens Before mechanical refrigeration systems were introduced, people cooled their food with ice and snow, either found locally or brought down from the mountains. Small Kitchen Appliances The familiar green plastic garbage bag (made from polyethylene) was invented by Harry Wasylyk in 1950. Electric Kettle Arthur Leslie Large invented the electric kettle in 1922.

General Electric introduced the electric kettle with an automatic cut-out in 1930. Weber Kettle Grill George Stephen invented the original Weber Kettle Grill in 1951. Mason Jar John Mason patented the screw neck bottle or the "Mason Jar" on November 30, 1858. Electric Mixers The first patent that can claim to be for an electric mixer was issued on November 17, 1885 to Rufus M. Eastman. Lillian Moller Gilbreth (1878-1972), the mother of 12 children, also patented an electric food mixer (at a later date). Ivar Jepson invented Sunbeam Mixmaster, which he patented in 1928, and first mass marketed in 1930. Paper Towels The Scott Paper Company was founded in Philadelphia by Irvin and Clarence Scott in 1879. Brothers Seymour and Irvin Scott ran a paper commission business for twelve years, but the poor economy in the 1870s forced them out of business. Irvin and his younger brother, Clarence, then decided to form their own company out of the remains of the first.

Irvin reportedly borrowed $2,000 from his father-in-law and added it to the $300 the two brothers had to form the capital of Scott Paper Company. In 1907, Scott Paper introduced the Sani-Towels paper towel, the first paper towels. They were invented for use in Philadelphia classrooms to help prevent the spread of the common cold from child to child. Peelers The nineteenth-century created numerous kitchen use inventions: toasters, potato mashers, apple/potato peelers, food choppers and sausage stuffers were all invented. Over 185 patents for coffee grinders and over 500 patents for apple/potato peelers were patented in the 1800s. Early peelers were made of iron and the patent number and other information was included in the casting. Peelers ranged from the familiar and simple round swiveling rod with a knife blade that peeled skin, to contraptions full of gears and wheels that could peel, core, slice and section. There were separate peelers designed for different fruits and vegetables; there were even peelers that removed the kernels from ears of corn.

Pressure Cooker In 1679, French physicist Denis Papin invented the pressure cooker, called Papin's Digester, this airtight cooker produced a hot steam that cooked food more quickly while preserving nutrients. Percy Spencer | Biography, Inventions and Facts Percy Spencer Percy Spencer invented “Microwave Oven” Percy Lebaron Spencer was an American inventor best known as the inventor of the microwave. Spencer was born in Howland, Maine in 1894. His father passed away when he was still a toddler and he was abandoned by his mother soon after. Spencer was brought up by his poverty-stricken uncle and aunt, who barely had enough to get by themselves. He was a curious child and once spent days exploring a log hauler truck that broke down in front of his house, trying to figure out how it worked. Spencer’s uncle died when he was seven years old, which made him the head of the family at a very early age. Soon after he left school to earn a living and support himself and his aunt. Between the ages of 12 and 16 he worked at a spool mill. Then he heard about an opening at a paper factory that was going to be run on electricity.

This was a new concept in the remote town where he lived, so he learned as much as he could about it and applied for the job of wiring the plant. Spencer was one of three people who got selected for the job, despite the fact that he had received no formal education or training in the field. At the age of 18, he joined the U.S. Navy and where he learnt all he could about wireless and radio technology. Spencer was strongly motivated to learn and gained expertise in a number of fields such as trigonometry, calculus, chemistry, physics, and metallurgy by reading extensively about them. Spencer was also an expert in radar tube design, and worked at a company called Raytheon as the chief of the power tube division. His expertise helped the company win a major contract from the U.S. government to produce magnetrons for radar equipments which was invaluable in the second world war. Under his leadership, the division expanded from a mere 15 employees to more than 5000 employees and productivity was also largely improved. His invention of the microwave cooking was purely coincidental, though.

One day while working at the plant, he crossed an active radar set when he noticed that the candy in his pocket had suddenly melted. His always active sense of curiosity was heightened and he decided to experiment further by testing out different types of food such as unpopped kernels of corn. To his surprise and delight, they began to pop. Unlike others who had experienced the same, Spencer was keen to learn more about it. After researching further and conducting more experiments, Percy Spencer filed for and successfully received a patent in 1945. In 1947, he produced the first commercially built microwave which was between 5 and a half to 6 feet tall and weighed around 750 lbs. It cost between $2000 to $3000 and was initially used in restaurants, railways and ships as they were too bulky and expensive for home use. It also had some shortcomings; for instance, meat would not cook properly in it. After further research and modification in design, the first microwave for home use was developed in 1967. It cost $495 and could be fit on a kitchen counter top.

In all, Spencer held more than 300 patents in his lifetime including those received at Raytheon where he eventually became a senior member of the Board of Directors. His notable awards include a Distinguished Public Service Award, a membership of the Institute of Radio Engineers, Fellowship of the American Academy of Arts and Sciences, and an honorary Doctor of Science from the University of Massachusetts. He died in 1970 at the age of 77. Household Appliances Timeline - Greatest Engineering Achievements of the Twentieth Century Household Appliances Timeline The technologies that created the 20th century's laborsaving household devices owe a huge debt to electrification, which brought light and power into the home. Then two major engineering innovations—resistance heating and small, efficient motors—led to electric stoves and irons, vacuum cleaners, washers, dryers, and dishwashers. In the second half of the century advances in electronics yielded appliances that could be set on timers and even programmed, further reducing the domestic workload by allowing washing and cooking to go on without the presence of the human launderer or cook. Engine-powered vacuum cleaner British civil engineer H. Cecil Booth patents a vacuum cleaner powered by an engine and mounted on a horse-drawn cart.

Teams of operators would reel the hoses into buildings to be cleaned. 1903 Lightweight electric iron introduced Earl Richardson of Ontario, California, introduces the lightweight electric iron. After complaints from customers that it overheated in the center, Richardson makes an iron with more heat in the point, useful for pressing around buttonholes and ruffles. Soon his customers are clamoring for the "iron with the hot point"—and in 1905 Richardson’s trademark iron is born. 1905 Electric filaments improved Engineer Albert Marsh patents the nickel and chromium alloy nichrome, used to make electric filaments that can heat up quickly without burning out. The advent of nichrome paves the way, 4 years later, for the first electric toaster. 1907 First practical domestic vacuum cleaner James Spangler, a janitor at an Ohio department store who suffers from asthma, invents his "electric suction-sweeper," the first practical domestic vacuum cleaner. It employs an electric fan to generate suction, rotating brushes to loosen dirt, a pillowcase for a filter, and a broomstick for a handle.

Unsuccessful with his heavy, clumsy invention, Spangler sells the rights the following year to a relative, William Hoover, whose redesign of the appliance coincides with the development of the small, high-speed universal motor, in which the same current (either AC or DC) passes through the appliance’s rotor and stator. This gives the vacuum cleaner more horsepower, higher airflow and suction, better engine cooling, and more portability than was possible with the larger, heavier induction motor. And the rest, as they say, is history. 1909 First commercially successful electric toaster Frank Shailor of General Electric files a patent application for the D-12, the first commercially successful electric toaster. The D-12 has a single heating element and no exterior casing. It has no working parts, no controls, and no sensors; a slice of bread must be turned by hand to toast on both sides. 1913 First refrigerator for home use Fred W. Wolf of Fort Wayne, Indiana, invents the first refrigerator for home use, a small unit mounted on top of an old-fashioned icebox and requiring external plumbing connections.

Only in 1925 would a hermetically sealed standalone home refrigerator of the modern type, based on pre-1900 work by Marcel Audiffren of France and by self-trained machinist Christian Steenstrup of Schenectady, New York, be commercially introduced. This and other early models use toxic gases such as methyl chloride and sulfur dioxide as refrigerants. On units not hermetically sealed, leaks—and resulting explosions and poisonings—are not uncommon, but the gas danger ends in 1929 with the advent of Freon-operated compressor refrigerators for home kitchens. 1913 First electric dishwasher on the market The Walker brothers of Philadelphia produce the first electric dishwasher to go on the market, with full-scale commercialization by Hotpoint and others in 1930. 1915 Calrod developed Charles C. Abbot of General Electric develops an electrically insulating, heat conducting ceramic "Calrod" that is still used in many electrical household appliances as well as in industry.

1919 First automatic pop-up toaster Charles Strite’s first automatic pop-up toaster uses a clockwork mechanism to time the toasting process, shut off the heating element when the bread is done, and release the slice with a pop-up spring. The invention finally reaches the marketplace in 1926 under the name Toastmaster. 1927 First iron with an adjustable temperature control The Silex Company introduces the first iron with an adjustable temperature control. The thermostat, devised by Joseph Myers, is made of pure silver. 1927 First garbage disposal John W. Hammes, a Racine, Wisconsin, architect, develops the first garbage disposal in his basement because he wants to make kitchen cleanup work easier for his wife. Nicknamed the "electric pig" when first introduced by the Emerson Electric Company, the appliance operates on the principle of centrifugal force to pulverize food waste against a stationary grind ring so it would easily flush down the drain. 1930s (Mid) Washing machine to wash, rinse, and extract water from clothes John W. Chamberlain of Bendix Corporation invents a device that enables a washing machine to wash, rinse, and extract water from clothes in a single operation.

This eliminates the need for cumbersome and often dangerous powered wringer rolls atop the machine. 1935 First clothes dryer To spare his mother having to hang wet laundry outside in the brutal North Dakota winter, J. Ross Moore builds an oil-heated drum in a shed next to his house, thereby creating the first clothes dryer. Moore’s first patented dryers run on either gas or electricity, but he is forced to sell the design to the Hamilton Manufacturing Company the following year because of financial difficulties. 1945 Magnetron discovered to melt candy, pop corn, and cook an egg Raytheon Corporation engineer Percy L. Spencer’s realization that the vacuum tube, or magnetron, he is testing can melt candy, pop corn, and cook an egg leads to the first microwave oven. Raytheon’s first model, in 1947, stands 5.5 feet tall, weighs more than 750 pounds, and sells for $5,000. It is quickly superseded by the equally gigantic but slightly less expensive Radarange; easily affordable countertop models are not marketed until 1967.

1947 First top-loading automatic washer The Nineteen Hundred Corporation introduces the first top-loading automatic washer, which Sears markets under the Kenmore label. Billed as a "suds saver," the round appliance sells for $239.95. 1952 First automatic coffeepot Russell Hobbs invents the CP1, the first automatic coffeepot as well as the first of what would become a successful line of appliances. The percolator regulates the strength of the coffee according to taste and has a green warning light and bimetallic strip that automatically cuts out when the coffee is perked. 1962 Spray mist added to iron Sunbeam ushers in a new era in iron technology by adding "spray mist" to the steam and dry functions of its S-5A model. The S-5A is itself an upgrade of the popular S-4 steam or dry iron that debuted in 1954. 1963 GE introduces the self-cleaning oven General Electric introduces the self-cleaning electric oven and in 1967 the first electronic oven control—beginning the revolution that would see microprocessors incorporated into household appliances of all sorts.

1972 First percolator with an automatic drip process Sunbeam develops the Mr. Coffee, the first percolator with an automatic drip process as well as an automatic cut-off control that lessens the danger of over-brewing. Mr. Coffee quickly becomes the country’s leading coffeemaker. 1978 First electronic sewing machine Singer introduces the Athena 2000, the world’s first electronic sewing machine. A wide variety of stitches, from basic straight to complicated decorative, are available at the touch of a button. The "brain" of the system is a chip that measures less than one-quarter of an inch and contains more than 8,000 transistors. 1990s Environmentally friendly washers and dryers Environmentally friendly washers and dryers that save water and conserve energy are introduced. They include the horizontal-axis washer, which tumbles rather than agitates the clothes and uses a smaller amount of water, and a dryer with sensors, rather than a timer, that shuts the appliance off when the clothes are dry. 1997 First prototype of a robotic vacuum cleaner Swedish appliance company Electrolux presents the first prototype of a robotic vacuum cleaner.

The device, billed as "the world’s first true domestic robot," sends and receives high-frequency ultrasound to negotiate its way around a room, much as bats do. In the production model, launched in Sweden a few years later, eight microphones receive and measure the returning signals to give the vacuum an accurate picture of the room. It calculates the size of a room by following around the walls for 90 seconds to 15 minutes, after which it begins a zigzag cleaning pattern and turns itself off when finished. Microwave Oven History - Invention of the Microwave Oven . MICROWAVE OVEN The microwave oven did not come about as a result of someone trying to find a better, faster way to cook. During World War II, two scientists invented the magnetron, a tube that produces microwaves. Installing magnetrons in Britains radar system, the microwaves were able to spot Nazi warplanes on their way to bomb the British Isles. By accident, several years later, it was discovered that microwaves also cook food. Called the Radar Range, the first microwave oven to go on the market was roughly as large and heavy as a refrigerator.

The idea of using microwave energy to cook food was accidentally discovered by Percy LeBaron Spencer of the Raytheon Company when he found that radar waves had melted a candy bar in his pocket. Experiments showed that microwave heating could raise the internal temperature of many foods far more rapidly than a conventional oven. The first Raytheon commercial microwave oven was the 1161 Radarange, which was marketed in 1954. Rated at 1600 watts, it was so large and expensive that it was practical only for restaurant and institutional use. In 1967, Amana, a division of Raytheon, introduced its domestic Radarange microwave oven, marking the beginning of the use of microwave ovens in home kitchens. Although sales were slow during the first few years, partially due to the ovens relatively expensive price tag, the concept of quick microwave cooking had arrived. In succeeding years, Litton and a number of other companies joined the countertop microwave oven market. By the end of 1971, the price of countertop units began to decrease and their capabilities were expanded. All electromagnetic energy can be characterized as waves with a specific wavelength and frequency distributed over a continuous range known as the electromagnetic spectrum.

For example, some radio waves have a wavelength of 6 feet (12 meters) and a frequency of 50 million hertz (Hz-cycles per second). Visible light waves have a wavelength of 400 to 700 millimicrons, and typical X-rays have a length of 0.01 millimicrons and a frequency of 30 x 10ï¿½ï¿½ millions. Microwaves (short waves or high frequency radio waves) are the shortest of radio waves, with a length of 0.1 millimeter and a frequency of 3 x 109 Hz. They are found in the non-ionizing portion of the energy spectrum, between radio waves and visible light. "Non-ionizing" means that microwaves do not detach charged particles and produce atoms with an unbalanced plus or minus charge. Microwaves can therefore safely produce heat and not cause food to become radioactive. Microwaves are reflected from most metals but they produce inductive resonance's in the atoms of many other substances. It was the discovery of their reaction to metals that led to the invention of radar.

It was their ability to produce resonant coupling that led to the invention of the microwave oven. TO LEARN MORE Biographies of Percy L. Spencer Inventors Highest Rated Percy L. Spencer ( 1894 - 1970 ) Category ( Inventors ) [ suggest a correction ] He was known as the inventor of the microwave but even though he possessed an ingenious mind, Percy L Spencer didn’t live a life of ease in the early years. Born in Maine, Percy was left an orphan at a young age. He never graduated from a traditional school but his brains carried him through life and never failed him. Percy L Spencer invented the microwave oven in 1945 which was after World War II. What is known today as a conventional kitchen feature began as a very unconventional discovery. Spencer discovered the microwave because he was at one of the Raytheon Companies when he noticed a sudden and odd feeling surge through his body. Around the same time, Percy Spencer realized that his chocolate candy bar was melting. As he noted these strange and peculiar happenings, he also recognized that both were a result of where he chose to stand.

Standing in front of a magnetron, Percy realized the power tube that drives the radar set was also capable of doing much more. He immediately took some kernels of popcorn and held it up to the magnetron. He watched with curiosity and splendid amazement as popcorn formed. From the experiment conducted at Raytheon, the microwave was developed. The first oven was basically developed for the use in commercial settings like restaurants and ocean vessels or railroad cars. These ovens weighed around seven hundred and fifty pounds. Today, the microwave oven is a familiar appliance in many homes across the world. Percy L. Spencer died in 1970. He left behind a lifetime of accomplishments. During his time at Raytheon, not only did he invent the microwave but he also held the position of Senior Vice-President of Raytheon. Percy L. Spencer secured over one hundred patents during his lifetime. Rating 5 MICROWAVE COOKING (Inventions) In Depth Tutorials and Information MICROWAVE COOKING (Inventions) The invention: System of high-speed cooking that uses microwave radition to agitate liquid molecules to raise temperatures by friction. The people behind the invention: Percy L.

Spencer (1894-1970), an American engineer Heinrich Hertz (1857-1894), a German physicist James Clerk Maxwell (1831-1879), a Scottish physicist The Nature of Microwaves Microwaves are electromagnetic waves, as are radio waves, X rays, and visible light. Water waves and sound waves are wave-shaped disturbances of particles in the media—water in the case of water waves and air or water in the case of sound waves—through which they travel. Electromagnetic waves, however, are wavelike variations of intensity in electric and magnetic fields. Electromagnetic waves were first studied in 1864 by James Clerk Maxwell, who explained mathematically their behavior and velocity. Electromagnetic waves are described in terms of their “wavelength” and “frequency.” The wavelength is the length of one cycle, which is the distance from the highest point of one wave to the highest point of the next wave, and the frequency is the number of cycles that occur in one second. Frequency is measured in units called “hertz,” named for the German physicist Heinrich Hertz.

The frequencies of microwaves run from 300 to 3,000 megahertz (1 megahertz equals 1 million hertz, or 1 million cycles per second), corresponding to wavelengths of 100 to 10 centimeters. Microwaves travel in the same way that light waves do; they are reflected by metallic objects, absorbed by some materials, and transmitted by other materials. When food is subjected to microwaves, it heats up because the microwaves make the water molecules in foods (water is the most common compound in foods) vibrate. Water is a “dipole molecule,” which means that it contains both positive and negative charges. When the food is subjected to microwaves, the dipole water molecules try to align themselves with the alternating electromagnetic field of the microwaves. This causes the water molecules to collide with one another and with other molecules in the food. Consequently, heat is produced as a result of friction. Development of the Microwave Oven Percy L. Spencer apparently discovered the principle of microwave cooking while he was experimenting with a radar device at the Raytheon Company. A candy bar in his pocket melted after being exposed to microwaves.

After realizing what had happened, Spencer made the first microwave oven from a milk can and applied for two patents, “Method of Treating Foodstuffs” and “Means for Treating Foodstuffs,” on October 8,1945, giving birth to microwave-oven technology. Spencer wrote that his invention “relates to the treatment of foodstuffs and, more particularly, to the cooking thereof through the use of electromagnetic energy.” Though the use of electromagnetic energy for heating was recognized at that time, the frequencies that were used were lower than 50 megahertz. Spencer discovered that heating at such low frequencies takes a long time. He eliminated the time disadvantage by using shorter wavelengths in the microwave region. Wavelengths of 10 centimeters or shorter were comparable to the average dimensions of foods. When these wavelengths were used, the heat that was generated became intense, the energy that was required was minimal, and the process became efficient enough to be exploited commercially. Although Spencer’s patents refer to the cooking of foods with microwave energy, neither deals directly with a microwave oven. The actual basis for a microwave oven may be patents filed by other researchers at Raytheon.

A patent by Karl Stiefel in 1949 may be the forerunner of the microwave oven, and in 1950, Fritz Gross received a patent entitled “Cooking Apparatus,” which specifically describes an oven that is very similar to modern microwave ovens. Perhaps the first mention of a commercial microwave oven was made in the November, 1946, issue of Electronics magazine. This article described the newly developed Radarange as a device that could bake biscuits in 29 seconds, cook hamburgers in 35 seconds, Percy L. Spencer Percy L. Spencer (1894-1970) had an unpromising background for the inventor of the twentieth century’s principal innovation in the technology of cooking. He was orphaned while still a young boy and never completed grade school. However, he possessed a keen curiosity and the imaginative intelligence to educate himself and recognize how to make things better. In 1941 the magnetron, which produces microwaves, was so complex and difficult to make that fewer than two dozen were produced in a day.

This pace delayed the campaign to improve radar, which used magnetrons, so Spencer, while working for Raytheon Corporation, set out to speed things along. He simplified the design and made it more efficient at the same time. Production of magnetrons soon increased more than a thousandfold. In 1945 he discovered by accident that microwaves could heat chocolate past the melting point. He immediately tried an experiment by training microwaves on popcorn kernels and was delighted to see them puff up straight away. The first microwave oven based on his discovery stood five feet, six inches tall and weighed 750 pounds, suitable only for restaurants. However, it soon got smaller, thanks to researchers at Raytheon. And after some initial hostility from cooks, it became popular. Raytheon bought Amana Refrigeration in 1965 to manufacture the home models and marketed them worldwide. Meanwhile, Spencer had become a senior vice president at the company and a member of its board of directors. Raytheon named one of its buildings after him, the U.S. Navy presented him with the Distinguished Service Medal for his contributions, and in 1999 he entered the Inventors Hall of Fame.

and grill a hot dog in 8 to 10 seconds. Another article that appeared a month later mentioned a unit that had been developed specifically for airline use. The frequency used in this oven was 3,000 megahertz. Within a year, a practical model 13 inches wide, 14 inches deep, and 15 inches high appeared, and several new models were operating in and around Boston. In June, 1947, Electronics magazine reported the installation of a Radarange in a restaurant, signaling the commercial use of microwave cooking. It was reported that this method more than tripled the speed of service. The Radarange became an important addition to a number of restaurants, and in 1948, Bernard Proctor and Samuel Goldblith used it for the first time to conduct research into microwave cooking. In the United States, the radio frequencies that can be used for heating are allocated by the Federal Communications Commission (FCC). The two most popular frequencies for microwave cooking are 915 and 2,450 megahertz, and the 2,450 frequency is used in home microwave ovens.

It is interesting that patents filed by Spencer in 1947 mention a frequency on the order of 2,450 megahertz. This fact is another example of Spencer’s vision in the development of microwave cooking principles. The Raytheon Company concentrated on using 2,450 megahertz, and in 1955, the first domestic microwave oven was introduced. It was not until the late 1960′s, however, that the price of the microwave oven decreased sufficiently for the device to become popular. The first patent describing a microwave heating system being used in conjunction with a conveyor was issued to Spencer in 1952. Later, based on this development, continuous industrial applications of microwaves were developed. Impact Initially, microwaves were viewed as simply an efficient means of rapidly converting electric energy to heat. Since that time, however, they have become an integral part of many applications. Because of the pioneering efforts of Percy L. Spencer, microwave applications in the food industry for cooking and for other processing operations have flourished.

In the early 1970′s, there were eleven microwave oven companies worldwide, two of which specialized in food processing operations, but the growth of the microwave oven industry has paralleled the growth in the radio and television industries. In 1984, microwave ovens accounted for more shipments than had ever been achieved by any appliance—9.1 million units. By 1989, more than 75 percent of the homes in the United States had microwave ovens, and in the 1990′s, microwavable foods were among the fastest-growing products in the food industry. Microwave energy facilitates reductions in operating costs and required energy, higher-quality and more reliable products, and positive environmental effects. To some degree, the use of industrial microwave energy remains in its infancy. New and improved applications of microwaves will continue to appear. See also Electric refrigerator; Fluorescent lighting; Food freezing; Robot (household); Television; Tupperware; Vacuum cleaner; Washing machine.

Question: Percy L. Spencer invented which household appliance in 1947?
Answer: THE MICROWAVE